1. Field of the Invention
The instant invention relates to method and appartus for the manufacture of transparent mirrored mini-balls for solar energy concentration and related applications. The mini-balls are in the size range of 4 microns (4×10−6 m) to 10 centimeters (10−1 m). In one form the mini-balls are transparent in at least one hemisphere, and have a mid-plane mirror. In another form, the mini-balls are quasi-hemispheres with a mirror on the flat top.
2. Description of the Prior Art
The manufacturing processes as taught herein are distinct and different from the prior art in at least two ways. First, none of the prior art is concerned with the manufacture of mirrors in transparent mini-balls, or on mini-balls. Second the prior art of others does not utilize reflecting mini-balls in the applications of the instant invention such as a Solar Concentrator, Optical Switching, Solar Propulsion Assist, and Active Reflection, Illumination, And Projection.
The U.S. patent application Ser. No. #2003/0117424 A1 of Kinoshita, Hayashi, and Ozaki, entitled COLORED ROTATION SPHERICAL MATERIAL, MANUFACTURING METHOD THEREFOR, AND DISPLAY DEVICE is concerned with enhancing the degree of whiteness of a ball in a display device. They have no transparent hemisphere and there is no specular mirror, both of which are key aspects of the instant invention. As stated in their Abstract:
“A colored rotation spherical material is configured so as to have two parts different from each other in color, such as a white part and a black part, and an optically reflective region between the two parts, such as a reflective layer. With this constitution, since the reflective layer reflects light which is usually absorbed in the black part, and the white part scatters the reflected light again, whiteness degree and reflectance increase.”
This Abstract well decribes their intent throughout the patent application. Since the reflective region between their two colored hemispheres is not really a mirror, it doesn't matter to them if it gets rough and distorts in their manufacturing process described in conjunction with FIGS. 2A–2C. That is why no steps are taken to prevent distortion during heat treatment of the laminated parts. In the manufacturing process described in conjunction with FIGS. 3A–3C the reflective region not only can distort, but it is distorted to begin with since it is just fine metal particles: “the reflective layer may be manufactured by preparing a reflective resin sheet 27 by diffusing metal fine spherical materials 26 in thermoplastic resin in advance as shown in FIG. 3A . . . . (Paragraph 0034, lines 2–5.) To further illustrate that they do not require a mirror surface, after discussing aluminum as a vapor deposited film or as a material for the fine dispersed particles they state: “it is also possible to use resin including arbitrary optical reflection feature inside as the reflective layer.” (Paragraph 0038, lines 4–6.) Their objective is just to enhance the white color in a display device. That is clearly why they are not trying to manufacture a mirror.